What Is Craniectomy Surgery?

This lifesaving procedure relieves pressure and bleeding in the brain

A craniectomy is a type of surgery that relieves pressure in the skull caused by a traumatic brain injury. This type of brain injury may cause bleeding and swelling in the brain, which can lead to dangerous intracranial pressure.

During a craniectomy, a portion of the skull is removed, allowing the brain to decompress.

This article discusses how and when a craniectomy is performed, the potential risks and complications, and how it differs from similar types of procedures.

The Difference Between Craniotomy and Craniectomy
Verywell / Gary Ferster

What Is a Craniectomy?

A craniectomy is a surgical procedure in which part of the skull is removed in order to relieve pressure in the brain. During a craniectomy, a neurosurgeon cuts through the scalp, folds back the skin, and then uses a surgical drill to remove a section of the skull, called a bone flap. This helps relieve swelling in the brain. The bone flap is typically round or oval.

A craniectomy is performed under general anesthesia. Prior to the surgery itself, the appropriate section of your scalp will be shaved and cleaned with an antiseptic.

What Is the Purpose of a Craniectomy?

A craniectomy is an emergency procedure used to relieve pressure in the skull due to an acute traumatic brain injury or a hemorrhagic stroke. If there is swelling or bleeding in the brain, pressure can build up, because there’s nowhere for it to go. A craniectomy prevents the brain from becoming compressed, a situation that can be fatal.

Potential Risks

Risks and complications that can occur after a craniectomy include:

  • Postoperative infection
  • Wound healing complications
  • Intracerebral hemorrhage
  • Extracranial cerebral herniation (when brain tissue pushes through the opening in the skull)
  • Leakage of cerebrospinal fluid
  • Fistulae
  • Seizures and epilepsy

Complications that can occur long after the surgery include:

  • Subdural hygroma (buildup of cerebrospinal fluid in the brain)
  • Hydrocephalus
  • Syndrome of the trephined (a group of symptoms including motor weakness, thinking and memory problems, headache, and seizures)

Craniectomy Recovery Time

It can take several weeks for your surgical site to heal after a craniectomy. During this time, you may need to wear a special helmet to protect your head and facilitate healing. You will be given pain medications; a nurse or other healthcare worker will tend to your surgical wound so it doesn’t become infected.

Eventually, you will undergo a follow-up surgery to replace the bone flap that was removed.

However, because a craniectomy is done in emergency situations involving very serious swelling of the brain, there is no typical length of a hospital stay or recovery time. Even after the surgical site heals, it is possible to require months and even years of rehabilitation if your brain has been severely damaged.

A brain injury can result in the loss of some physical and/or cognitive abilities. Depending on a person’s specific needs, they may require physical therapy, occupational therapy, cognitive therapy, and speech therapy.

Similar Procedures

Other procedures that involve opening the skull include:


In a craniotomy, a piece of the skull is also removed. However, the purpose of a craniotomy is typically to allow a surgeon access to the brain in order to remove a brain tumor, as opposed to relieving swelling in the brain.

A craniotomy can be performed under general anesthesia. In some cases, however, a patient may only be lightly sedated with the surgical area numbed; this is called an awake craniotomy. Awake craniotomies are typically performed when the lesions are in areas of the brain that control speech and motor function.

Craniotomies can also be used to clip an aneurysm. A brain aneurysm is a bulging area in a weakened brain artery that is at risk of rupturing, potentially causing a hemorrhagic stroke or death. To prevent this possibility, a surgeon places a metal clip across the “neck” of the aneurysm to prevent rupture.

Burr Hole Surgery

Unlike with a craniotomy and craniectomy, a burr hole procedure does not involve removal of a bone flap. Instead, the surgeon makes one or more small holes in the skull with a surgical drill. Burr hole surgery is performed under general anesthesia.

The primary reason for burr hole surgery is to treat a subdural hematoma. Subdural hematomas can be acute in the case of a mild brain injury due to a fall or a sports injury. Chronic hematomas are more common in older people who take anticoagulant medications, or in those who drink alcohol heavily. Both types can lead to a buildup of pressure in the brain that can be relieved with burr hole surgery.

The Bone Flap 

One of the key differences between a craniectomy and a craniotomy is what happens to the bone flap after the necessary surgery is performed.

In a craniotomy, the bone flap is usually reattached with plates, sutures, or wires, allowing it to heal and mend like any other broken bone. After several months, the bone is nearly as strong as it was prior to surgery.

A craniectomy also includes the removal of a bone flap, but in this case, it is not returned to its location after the procedure is finished. This may be because the bone itself is too damaged, the brain is too swollen to reattach the flap, or the surgeon feels it is in the patient’s best interest not to replace it.

If there is an infection in the area, for example, the bone flap may be discarded. If a bone flap is removed, but not able to be returned during the procedure, it can still be put back into place at a later time.

In this situation, the surgeon will place the bone flap in another location. In most cases, the surgeon will make an incision in the abdomen, large enough to slip the piece of bone inside like an envelope under the fatty tissue of the belly. There it is protected and preserved by the patient’s own body. A bone flap can also be placed in a special deep freezer in the hospital lab for storage until it can be replaced.

If the bone flap cannot be returned, prosthetics and artificial bone are also available to aid the reconstruction at a later date. Replacing the missing piece is important because the brain is minimally protected without the bone in place. Like the “soft spot” on a newborn’s head, the lack of bone could make it possible for a penetrating brain injury to occur.

A Word From Verywell 

Brain surgery is a very serious procedure under any circumstances, but a craniectomy is done when there is an immediate risk to the brain and neurological function due to severe brain injury or stroke.

If you or a loved one has sustained brain damage, you will be referred to a specialized rehabilitation facility where you can work on regaining as much physical and cognitive function as possible. There are also numerous organizations geared to supporting those with brain injuries, including the Brain Injury Association of America.

Frequently Asked Questions

  • Why does a bone flap need to be placed in the stomach after a craniectomy?

    A bone flap may need to be reattached to the skull at a later date after a craniectomy. This may be necessary to allow the swelling in the brain to subside. In this case, it is common for the surgeon to make an incision in the patient’s abdomen and store the piece of bone under the fatty tissue of the belly in order to preserve it until it can be reattached.

  • Does the surgeon reattach the bone flap after a craniotomy?

    In a craniotomy, the surgeon replaces the bone flap right after the brain surgery, using sutures, plates, and wires. That portion of the skull will then heal and mend just like any other bone.

  • How does craniotomy surgery differ from a craniectomy?

    A craniectomy is an emergency procedure used to relieve swelling in the brain due to a stroke or a traumatic brain injury. A craniotomy is done in order to allow a surgeon to remove a brain tumor.

    In both cases, a bone flap, or section of the skull, is removed. With a craniotomy, this bone flap is replaced right away, while in a craniectomy the flap is often preserved and put back at a later time.

  • What is the survival rate of a craniectomy?

    The survival rate for craniectomy depends on many factors, such as the age of the person and the extent of the head injury. Other injuries that may have been sustained at the same time as the head injury can also play a role in survival. Studies have found varying mortality rates at 30 days after the procedure, but they can be as high as 26%. Deaths after craniectomy are often related to ongoing brain damage.


13 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Jennifer Whitlock, RN, MSN, FN
Jennifer Whitlock, RN, MSN, FNP-C, is a board-certified family nurse practitioner. She has experience in primary care and hospital medicine.